Entity:
What type of plant is best suited for testing under windy conditions?
What general care is needed for these plants?
What effect will variations in plant size/shape have on growth under windy conditions and how can this be accounted for?

Independent Variable:
How long does a plant need to be exposed to a high wind environment before an effect is measurable?
How can wind be artificially controlled for an experiment?

Dependent Variable:
What measures will be used to collect qualitative and quantitative experimental data? I'm really interested in how you will measure "effects" of wind. What sort of things are you thinking about? Are you measuring actual growth (if so, of what? leaf, stem, # of leaves, root) or strength of plant (if measured how)?

Connections:
How does varying amounts of time spent in a high wind environment effect plant growth?

(Just thought of something else you'll need to consider for your constants. My guess is you've thought of water, but how do you keep that constant? If plants are in different windy scenarios, the soil will dry out at different rates. Does keeping water constant mean watering all the plants equally? or does it mean their soil remains at the same moisture level? Just some food for thought!, BTW there isn't really a "right" answer as long as you can justify the method you choose.)

Can you change your DV question to be more specific? Then I'll put a grade in the grade book for you.